Term
| Where does primary hyperthyroidism occur? |
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Definition
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Term
| Roughly what percentage of primary thyroid disease is benign? Give some examples. |
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Definition
->98%
-adenomatous hyperplasia
-adenoma |
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Term
| Roughly what percentage of primary thyroid disease is malignant? Give some examples? |
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Definition
-<2% malignant
-adenocarcinoma |
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Term
| What it the typical signalment of hyperthyroidism? |
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Definition
-older: average age 12-13y
-no sed or breed predilections |
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Term
| What are the clinical signs of hyperthyroidism from most to least common? |
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Definition
-weight loss
-polyphagia
-hyperactivity
-PU/PD
-vomiting
-diarrhea
-panting
-weakness |
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Term
| Roughly what percentage of cats with hyperthyroidism have apathetic hyperthyroidism? WHat are the clinical signs? |
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Definition
-<10%
-anorexia and lethargy |
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Term
| What is the clinical significance of apatehtic hyperthyroidism? |
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Definition
| -search for concurrent illness: CHF and neoplasia |
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Term
| What signs do we see on physical exam with cats with hyperthyroidism? |
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Definition
-poor body condition
-unkept hair coat
-agitated
0thyroid slip (>80%), not specific
=CV: mimics HCM, tachycardia, gallop rhythm, murmur
-tachypneic |
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Term
| What do we see on CBC with hyperthyroid cat? |
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Definition
-BCT high in cat > 12y
-stress leukogram |
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Term
| What do we see on biochem analysis with a hyperthyroid cat? |
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Definition
-elevated liver enzymes with normal serum bilirubin
-hyperglycemia: stress-induced
-inc BUN:Creatinie ration (inc dietary protein and dec muscle mass)
-hypocholesterolemia: lipid metabolism |
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Term
| What do we see on UA with hyperthyroidism? |
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Definition
-DIlute urine (USG < 1.035)
-proteinuria
022% have bacterial UTI |
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Term
| What other diagnostic tests and their results do we see with hyperthyroidism? |
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Definition
-urine culture
-BP
-/+ thoracic rads: signs of resp dz or dyspnea
-/+ echocardiogram: heart murmur, gallop rhythm, signs of CHF
-abdominal US: not routinely recommend |
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Term
| How do we definitively diagnose thyroidism? |
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Definition
-strong clinical suspicion: clinical findings
-Total T4 |
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Term
| If you see clinical signs that suggest hyperthyroidism but your TT4 is on the upper end of normal what do you do? |
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Definition
-retest in 1-3m
-free T4
-Technetium scan
-T3 suppression test
-Trial treatment |
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Term
| What results do we expect on a Technetium scan with hyperthyroidism? |
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Definition
| -uptake of thyroid gland should be higher than salivary glands |
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Term
| HOw do we perform a technetium scan? |
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Definition
| -administer IV and scam with a gamma camera |
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Term
| How do we perfomr a T3 suppression test? What are our normal results? What are our hyperthyroidism results? |
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Definition
-measure T4, administer T3, then measure T4 & T3
-normal = suppression
-HyperT = fails to suppress |
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Term
| How do we treat hyperthyroidism? |
|
Definition
-thioureylene antihyroid drugs: Methimazole or carbimazole
-radioactive iodine
-surgical thyroidectomy: only with adenocarcinoma |
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Term
| How does Methimazole work? Dose? When do we recheck it? |
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Definition
-inhibits iodide incorporation
-2.5 mg PO BID (better) or 5 mg/kg SID
-recheck T4 2-3w until euthyroid & inc dose 25-50% until euthyroid |
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Term
| What are the side effects of Methimazole? |
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Definition
-vomiting/diarrhea/anorexia: most common
-hepatopathy
-bone marrow suppression
-facial excoriation |
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Term
| How do we monitor Methimazole? What do we do if we have severe GI side effects? What do we do if we have other side effects? |
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Definition
-CBC and biochem q2-3w initially
-trandermal formulation
-Discontinue drug |
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Term
| How does radioactive iodine (I131) treat hyperthyroidism? How is it administered? |
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Definition
-destroys tissue within 2mm distance
-administered SQ |
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Term
| How well does I131 treatment work for hyperthyroidism? What are its downsides? |
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Definition
->90% work
-requires special facilities, specieal training, isolation for 1w, larger cost, and permanent |
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Term
| What are the major downsides to iodine restricted diet (Hill's Y/D) to treat hyperthyroidism? |
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Definition
-cannot eat any other food or treats
-takes long time to achieve euthyroid
-may not alleviate clinical signs |
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Term
| Is thyroidectomy appropriate for routine hyperthyroid treatment? If not, when do we use it? |
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Definition
-NO
-reserved for thyroid carcinoma |
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Term
| What are the common complications seen with thyroidectomy? |
|
Definition
-hypoparathyroidism
-hemorrhage
-laryngeal paralysis
-Horner's syndrome |
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